The purpose of this protocol is to quantify Hepatitis C Virus (HCV) levels circulating in blood before, during, and after treatment in patients either entering study protocols (separately submitted) or being treated with alpha interferon-2B which is FDA approved for the treatment of chronic HCV, and to quantify the variation time of circulating HCV levels in patients who either refuse treatment or have a contradiction to therapy; in order to study the natural history of HCV.